What Is It?
The birth control pill (also called "the Pill") is a
daily pill that contains hormones to change the way the body works
and prevent pregnancy. Hormones are chemical substances that
control the functioning of the body's organs. In this case, the
hormones in the Pill control the ovaries and the uterus.
How Does It Work?
Most birth control pills are "combination pills"
containing a combination of the hormones estrogen and
progesterone to prevent ovulation (the release of an egg
during the monthly cycle). A woman cannot get pregnant if she
doesn't ovulate because there is no egg to be fertilized. The
Pill also works by thickening the mucus around the cervix, which
makes it difficult for sperm to enter the uterus and reach any eggs
that may have been released. The hormones in the Pill can also
sometimes affect the lining of the uterus, making it difficult for
an egg to attach to the wall of the uterus.
Most combination pills come in either a 21-day pack or a 28-day
pack. One hormone pill is taken each day at about the same time for
21 days. Depending on your pack, you will either stop taking birth
control pills for 7 days (as in the 21-day pack) or you will take a
pill that contains no hormones for 7 days (the 28-day pack). A
woman has her period when she stops taking the pills that contain
hormones. Some women prefer the 28-day pack because it helps them
stay in the habit of taking a pill every day.
There is also a type of combination pill that decreases the
frequency of a woman's period by supplying a hormone pill for
12 weeks and then inactive pills for 7 days. This decreases the
number of periods to one every 3 months instead of one every
month.
Another kind of pill that may change the number of monthly
periods is the low-dose progesterone pill, sometimes called the
mini-pill. This type of birth control pill differs from the other
pills in that it only contains one type of hormone - progesterone -
rather than a combination of estrogen and progesterone. It works by
changing the cervical mucus and the lining of the uterus, and
sometimes by affecting ovulation as well. The mini-pill can be
slightly less effective at preventing pregnancy.
The mini-pill is taken every day without a break. A girl who is
taking the mini-pill may have no period at all or she may go
several months without a period. For the minipill to work, it must
be taken at the same time every day, without missing any doses.
Any type of birth control pill works best when it is taken
every single day at the same time of day, regardless of whether a
girl is going to have sex. This is
especially important
with progesterone-only pills.
For the first 7 days of taking the Pill, a girl should use an
additional form of contraception, such as condoms, to prevent
pregnancy. After 7 days, the Pill should work alone to prevent
pregnancy. But continuing to use
condoms
will protect against
sexually transmitted diseases (STDs)
.
If pills are skipped or forgotten, a girl is not protected
against pregnancy and she will need a backup form of birth control,
such as condoms. Or she will need to stop having sex for a while.
Do not
take a friend's or relative's pills.
How Well Does It Work?
Over the course of 1 year, 5 to 8 out of 100 typical couples who
rely on the Pill to prevent pregnancy will have an accidental
pregnancy. Of course, this is an average figure and the chance of
getting pregnant depends on whether you take your birth control
pills every day. The Pill is an effective form of birth control,
but even missing 1 day increases the chance of getting
pregnant.
In general,
how well
each type of birth control method works depends on a lot of things.
These include whether a person has any health conditions or is
taking any medications or herbal supplements that might interfere
with its use. For example, antibiotics or an herb like St.
John's wort can interfere with the effectiveness of the
Pill.
How well a particular method of birth control works also depends
on whether the method chosen is convenient - and whether the person
remembers to use it correctly
all the time
.
Protection Against STDs
The birth control pill
does not
protect against STDs. Couples having sex must always use
condoms along with the Pill to protect against STDs.
Abstinence (the decision to not have sex) is the
only
method that always prevents pregnancy and STDs.
Possible Side Effects
The birth control pill is a safe and effective method of birth
control. Most young women who take the Pill have none to very few
side effects. The side effects that some women have while on the
Pill include:
- irregular menstrual bleeding
- nausea, weight gain, headaches, dizziness, and breast
tenderness
- mood changes
- blood clots (rare in women under 35 who do not smoke)
Some of these side effects improve over the first 3 months on
the Pill. When a girl has side effects, a doctor will sometimes
prescribe a different brand of the Pill.
The Pill also has some side effects that most girls are happy
about. It usually makes periods much lighter, reduces cramps, and
is often prescribed for women who have
menstrual problems
. Taking the Pill often improves acne, and some doctors prescribe
it for this purpose. Birth control pills have also been found to
protect against some forms of breast disease, anemia, ovarian
cysts, and ovarian and endometrial cancers.
Who Uses It?
Young women who can remember to take a pill each day and who
want excellent protection from pregnancy use birth control
pills.
Not all women can - or should - use the Pill. In some cases,
medical or other conditions make the use of the Pill less effective
or more risky. For example, it is not recommended for women who
have had blood clots, certain types of cancers, or certain types of
migraine headaches. It's recommended that girls who have had
unexplained vaginal bleeding (bleeding that is not during their
periods) or who suspect they may be pregnant should talk to their
doctor.
Girls who are interested in learning more about different types
of birth control, including the Pill, should talk to their doctors
or other health professionals.
How Do You Get It?
A doctor or a nurse practitioner must prescribe the Pill. He or
she will do a complete physical exam, which may include a pelvic
exam. The doctor or nurse will often prescribe 3 months' worth
of pills and explain when to begin taking the Pill and what to do
if pills are missed.
The doctor or nurse will usually ask the girl to come back in 3
months to have her blood pressure checked and to see if she is
having any problems.
If there are no problems and a girl wants to continue to
use the Pill, the doctor or nurse will probably write another
prescription for 6 to 12 months. After that, girls who are having
sex should get routine exams every 6 months to a year, or as
recommended by a doctor.
How Much Does It Cost?
The Pill usually costs between $20 and $50 a month, depending on
the type. Many health and family planning clinics (such as Planned
Parenthood) sell birth control pills for less. In addition, birth
control pills and doctor visits are covered by many health
insurance plans.
Reviewed by:
Larissa Hirsch, MD
Date reviewed: February 2007
Originally reviewed by:
Neil Izenberg, MD, and George A. Macones, MD
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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